1. Field of the Invention
This invention relates to a method of chain extending organosiloxanes.
2. Description of the Prior Art
The methylvinyldi-(epsilon-caprolactamo)silane is known from an article by K. A. Andrianov et al., entitled "Reaction of Alkyl(aryl)chlorosilanes and Alpha,omega-dichloromethylsiloxanes With Epsilon-caprolactam and Alpha-pyrrolidone", in Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 5, pp. 1150-1152, May, 1972; CB Trans, pp. 1100-1102.
A number of silanes have been known to chain extend hydroxyl endblocked polydiorganosiloxanes. Such a silane is methylvinyldi-(N-methylacetamido)silane which is described as an in situ chain extender in low modulus room temperature vulcanizable silicone elastomer compositions. This is described by Toporcer et al. in U.S. Pat. No. 3,776,934. An application by I. D. Crossan and L. H. Toporcer, Ser. No. 596,475, filed July 16, 1975 and entitled "Method of Increasing the Molecular Weight of Hydroxyl Endblocked Polydiorganosiloxanes" and now U.S. Pat. No. 4,020,044 describes using certain methylvinyldi-(N-organoacetamido)silanes to chain extend hydroxyl endblocked polydiorganosiloxanes by mixing the two components.
Not all dihydrolyzable silanes will act as chain extenders for hydroxyl endblocked polydiorganosiloxanes. Whereas some such silanes are known, there is still room for improved methods of chain extending, such as faster at room temperature, non-reactive by-products, non-toxic by-products, odorless by-products, high yield of product, clean reactions and the like.